add generics support

dist/index.d.ts

@@ -45,8 +45,11 @@ export interface NotOp {
     not: Expression;
 }
 export declare type Expression = FuncOp | AndOp | OrOp | NotOp | CompareOp;
-export declare type Func = (param: any, context: any) => boolean;
-export declare type FunctionsTable = {
-    [k: string]: Func;
+export declare type Func<T> = (param: any, context: T) => boolean;
+export declare type FunctionsTable<T> = {
+    [k: string]: Func<T>;
 };
-export declare const evaluate: (expression: Expression, context: any, functionsTable: FunctionsTable) => boolean;
+export interface Context {
+    [index: string]: any;
+}
+export declare const evaluate: <T extends Context>(expression: Expression, context: T, functionsTable: FunctionsTable<T>) => boolean;

dist/index.js

@@ -10,7 +10,7 @@ function isNotOp(expression) {
     return expression.not !== undefined;
 }
 const _isObject = (obj) => {
-    var type = typeof obj;
+    const type = typeof obj;
     return type === 'function' || type === 'object' && !!obj;
 };
 const _evaluateCompareOp = (op, param) => {

example/lib/functionsFactory.d.ts

@@ -1,8 +1,9 @@
 import { Func, FunctionsTable } from "../../dist";
+import { ExpressionContext } from "./evaluator";
 export interface FunctionDescription {
     name: string;
-    evaluate: Func;
+    evaluate: Func<ExpressionContext>;
 }
 export declare type FuncFactory = () => FunctionDescription;
-declare const functionsTable: FunctionsTable;
+declare const functionsTable: FunctionsTable<ExpressionContext>;
 export { functionsTable };

example/lib/functionsFactory.ts

@@ -3,17 +3,18 @@
 import * as fs from 'fs';
 import * as path from 'path';
 import {Func, FunctionsTable} from "../../dist";
+import {ExpressionContext} from "./evaluator";
 
 export interface FunctionDescription {
     name: string;
-    evaluate: Func;
+    evaluate: Func<ExpressionContext>;
 }
 
 export type FuncFactory = () => FunctionDescription;
 
 const functionsDir = path.join(__dirname, '/functions');
 
-const functionsTable: FunctionsTable = {};
+const functionsTable: FunctionsTable<ExpressionContext> = {};
 
 fs.readdirSync(functionsDir).forEach((file) => {
   if (file.endsWith('.js')) {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "json-expression-eval",
-  "version": "1.1.0",
+  "version": "1.1.1",
   "description": "evaluate a json described boolean expression using dynamic functions",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

src/index.ts

@@ -60,9 +60,9 @@ export interface NotOp {
 
 export type Expression = FuncOp | AndOp | OrOp | NotOp | CompareOp;
 
-export type Func = (param: any, context: any) => boolean;
+export type Func<T> = (param: any, context: T) => boolean;
 
-export type FunctionsTable = { [k: string]: Func };
+export type FunctionsTable<T> = { [k: string]: Func<T> };
 
 function isAndOp(expression: Expression): expression is AndOp {
     return (<AndOp>expression).and !== undefined;
@@ -77,7 +77,7 @@ function isNotOp(expression: Expression): expression is NotOp {
 }
 
 const _isObject = (obj: any) => {
-    var type = typeof obj;
+    const type = typeof obj;
     return type === 'function' || type === 'object' && !!obj;
 };
 
@@ -108,7 +108,11 @@ const _evaluateCompareOp = (op: CompareOp, param: any) : boolean => {
     throw new Error(`Invalid expression - unknown op ${key}`);
 };
 
-export const evaluate = (expression: Expression, context: any, functionsTable: FunctionsTable): boolean => {
+export interface Context {
+    [index:string] : any;
+}
+
+export const evaluate = <T extends Context>(expression: Expression, context: T, functionsTable: FunctionsTable<T>): boolean => {
     const _evaluate = (_expression: Expression): boolean => {
         const keys = Object.keys(_expression);
         if (keys.length !== 1) {